Effect of pennyroyal (Mentha pulegium L.) extract on performance, blood constitutes, immunity parameters and intestinal microflora in broiler chickens

This study aimed to test the hypothesis that lower levels of pennyroyal (Mentha pulegium L.) extract can improve growth traits, blood constitutes, immunity and microflora in broilers up to 42-days production cycle. A total of 300 broiler chicks (Ross 308) were randomly distributed into five dietary treatments, with three replicates per treatment (20 birds per replicate) as follows: control group received a basal diet with no pennyroyal supplementation, whereas the treatment-groups fed the basal diet including different pennyroyal levels (100, 200, 300 and 400 ppm, respectively) in drinking water. Feeding of pennyroyal during the whole rearing period partly affected body weight gain (BWG), feed intake (FI) and feed conversion ratio (FCR) of broilers. Pennyroyal extract at different levels significantly lowered blood total cholesterol and triglycerides of birds. Results also showed significantly higher high-density lipoprotein (HDL)-cholesterol and lower low-density lipoprotein (LDL)-cholesterol levels in pennyroyal-supplemented group. Further, a significant increase of antibody production to total sheep red blood cells (SRBC) and IgM at 42 days of age was observed. Broilers receiving 100 ppm pennyroyal extract had the lowest count of E. coli bacteria in ileum. Overall, based on our findings, supplementing pennyroyal affected positively broiler growth traits, blood parameters and reduced harmful intestinal bacteria.